The History Channel has been airing a bunch of shows on the creation of our universe lately, and it got me to thinking about something I think about from time to time.
The number of events and coincidences that had to come together in order for life to develop on this planet is staggering. The planet needed to be just the right size in order to maintain an atmosphere. It had to be just the right distance from the sun in order to allow for liquid water. It had to have a large moon to stabilize its rotation and tidal forces. It had to have plate tectonics to dissipate heat from the core. The proper elements, minerals, and climate needed to exist to spark the initial chemical reactions that gave rise to life. Then, once life developed, it took a truly miraculous chain of events to bring about a life form as intelligent as humans.
I firmly believe that the development of intelligent life in the universe is such an absurdly rare event that we'll probably never, in the entire lifespan of our planet, identify another planet harboring intelligent life. The odds are simply that small.
However, it's estimated that there are between 100 billion and 300 billion planets in our galaxy and about 100 billion galaxies in the known universe. Even if we said the chances of intelligent life developing is so rare that it is 1 in a billion, that means there are a billion planets in the universe with intelligent life.
That's a billion civilizations that we'll never know. A billion lifeforms that we'll never be able to learn from or observe. Perhaps all of them are like ourselves, isolated by thousands of light years from the other intelligent civilizations, trying desperately to unlock the secrets of the universe and find out if they're all alone.
The immense size of the universe is staggering. We can't possibly comprehend just how big it is.
This is the famous Hubble Deep Field image. It represents 2 parts in a million of the entire sky. There are about 1,500 galaxies visible in the image each with billions of stars. To say that the Earth is just 1 grain of sand out of all the beaches in the entire world compared to the universe is a great exaggeration.
Anyway... that was my mind blowing thought of the day.